Magnetic Bearings and Heat

One of the main problems associated with the design and application of active magnetic bearings is overheating. Heat is generated by two main mechanisms. The first heat source is due to eddy current loss. Eddy current is the current driven in the conductor by the dynamic magnetic field placed in the conductor. The eddy current loss in the magnetic bearing is caused by the rate of change of the magnetic field. Relative motion generates rotating current in the conductor, which leads to loss of efficiency.

Introduction Magnetic bearings are bearings that use magnetic levitation to withstand loads. Scientists first discovered the magnetic effect of magnetic minerals around 500 BC. In the latter part of the 20th century, scientists began studying ways to incorporate this magnetic effect into the bearings to form magnetic bearings. - INTRODUCTION: The world's largest and most powerful particle collision device, based in the European nuclear research center located on the French-Swiss border, is a tough task. It is designed to help scientists discover the composition of the earth; it is also an important part of the scientific solving theory. It is a 27 kilometer ring with a super magnet that helps particles accelerate along the way.

Magnetic bearings are magnetic bearings that use magnetic levitation to balance the load. Magnetic bearings support moving parts without physical contact. Magnetic bearings have therefore been used in various industrial fields for over a decade and their advantages include non-contact rotor support, no lubrication, or even friction. Today, two types of magnetic bearing technology are used. They are passive and active. Passive bearings are now similar to mechanical bearings and do not require active control to operate. In the active system, the contact position sensor continuously monitors the position of the shaft and does not provide this information to the control system. This is based on the response of the system command to the actuator via the current amplifier. Next, these currents are converted into magnetic force by the actuator, they are applied to the rotor to adjust the position, giving a certain attenuation.

Magnetic bearings consist of electronic components such as sensors, power amplifiers and microprocessors. The core of the active magnetic bearing system is software. Compared to conventional bearings, the system becomes powerful by sensing function, information flow, and drive from microprocessor. Additional bearings are required, which can be ball bearings or journal bearings. These bearings do not come into contact with the rotor during normal operation. When overloading or malfunctioning the magnetic bearing, it is necessary to operate in a short time. They do not allow the rotor to touch the casing until the rotor stops or AMB regains the rotor.